How to check whether a Sensor IPMC threshold is set?


When programming sensors there are a choice of 6 thresholds to set:
It is usual for experts to program only some of these thresholds and depends on the sensor type. For example:
On the WinCC side it is useful to be able to iterate over and read back the thresholds on the devices and set alerts at the corresponding values. The problem is that for the thresholds that have not been set the value returned is zero. Then it is difficult to work out if it is not set or set to 0. Is there a flag that says whether the threshold is set or not? Otherwise we will have to do some educated guessing as to what was intended for the different permutations.
Failing that should we impose that all developers implement all 6 threshold levels in numerical order e.g. -999,10,11,39,40,60 in the above example?

This question has been solved via e-mail, the ticket is available on the cern-ipmc webapplication: